From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: Strange error in domU after dom0 update Date: Thu, 22 Oct 2009 14:08:57 -0700 Message-ID: <4AE0C9E9.4010405@goop.org> References: <20091022094717.fk8pkqy6o80kgg0w@webmail.flonatel.org> <20091022110131.GO1434@reaktio.net> <20091022135508.4pwk6lslroc8oosc@webmail.flonatel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20091022135508.4pwk6lslroc8oosc@webmail.flonatel.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Andreas Florath Cc: Xen-devel List-Id: xen-devel@lists.xenproject.org On 10/22/09 04:55, Andreas Florath wrote: > What I recognized is, that the domU on xen-unstable is somewhat slower > than on the working xen-3.2.1 system. Had a closer look at the boot > messages and found one difference: > > xen-3.2.1 system: > [ 0.000000] Xen reported: 2793.000 MHz processor. > > xen-unstable: > [ 0.000000] Xen reported: 1000.000 MHz processor. > > Except from /proc/cpuinfo of the dom0 (both versions): > model name : Intel(R) Pentium(R) 4 CPU 2.80GHz > cpu MHz : 2793.002 > > I'm completely unsure if this has something to do with the problem - > but at least it can explain something. > > Can anybody please tell me, if this is a bug or a feature - or maybe > even a configuration parameter? xen-unstable currently always traps and emulates rdtsc, so that tsc appears to be running at 1GHz. Set "tsc_native = 1" in your config file to return to the old behaviour. It shouldn't have a dramatic effect on your domain's performance (perhaps a few percent improvement). J